U.S. patent number 7,900,373 [Application Number 10/511,335] was granted by the patent office on 2011-03-08 for method for conditioning semiconductor wafers and/or hybrids.
This patent grant is currently assigned to ERS Electronic GmbH. Invention is credited to Erich Reitinger.
United States Patent |
7,900,373 |
Reitinger |
March 8, 2011 |
Method for conditioning semiconductor wafers and/or hybrids
Abstract
The present invention provides a method for conditioning
semiconductor wafers and/or hybrids having the steps: preparation
of a space (1) which is at least partially enclosed and has a
wafer/hybrid holding device (10) which is located therein and has
the purpose of holding a semiconductor wafer and/or hybrid; and
conduction of a dry fluid through the wafer/hybrid holding device
(10) in order to heat-treat the wafer/hybrid holding device (10);
wherein at least a portion of the fluid leaving the wafer/hybrid
holding device (10) is used to condition the atmosphere within the
space (1). The invention also provides a corresponding device for
conditioning semiconductor wafers and/or hybrids.
Inventors: |
Reitinger; Erich (Munich,
DE) |
Assignee: |
ERS Electronic GmbH (Germering,
DE)
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Family
ID: |
28798441 |
Appl.
No.: |
10/511,335 |
Filed: |
April 15, 2003 |
PCT
Filed: |
April 15, 2003 |
PCT No.: |
PCT/EP03/03937 |
371(c)(1),(2),(4) Date: |
May 05, 2005 |
PCT
Pub. No.: |
WO03/088323 |
PCT
Pub. Date: |
October 23, 2003 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20050227503 A1 |
Oct 13, 2005 |
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Foreign Application Priority Data
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Apr 15, 2002 [DE] |
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102 16 786 |
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Current U.S.
Class: |
34/381;
324/750.08; 34/497; 34/495; 34/492; 118/712; 34/413 |
Current CPC
Class: |
H01L
21/67109 (20130101) |
Current International
Class: |
F26B
11/06 (20060101) |
Field of
Search: |
;34/77,78,80,380,381,413,495,497,492 ;118/712 ;324/760 |
References Cited
[Referenced By]
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Other References
First Examiner's Report dated Feb. 23, 2009 in corresponding
Canadian Appln. No. 2,481,260. cited by other.
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Primary Examiner: Gravini; Stephen M.
Claims
The invention claimed is:
1. A method for conditioning semiconductor wafers and/or hybrids
comprising: preparing a space which is essentially enclosed by a
container and has a wafer/hybrid chuck which is located therein and
has the purpose of holding a semiconductor wafer and/or hybrid
applied to the wafer/hybrid chuck; pre-cooling a dry fluid in a
single heat exchanger outside the space; conducting the pre-cooled
fluid out of the single heat exchanger into the wafer/hybrid chuck
via a first line, and then through the wafer/hybrid chuck to cool
the wafer/hybrid chuck; conducting at least a portion of the fluid
having been conducted through the wafer/hybrid chuck back to the
single heat exchanger via a second line out of the wafer/hybrid
chuck to the single heat exchanger; and heating the portion, by
using a residual coldness of the portion to cool the single heat
exchanger to contribute to the pre-cooling of the fluid in the
single heat exchanger, wherein the heated portion is conducted via
a third line from the single heat exchanger into the space, before
being allowed to flow out within the space to condition the
atmosphere in the space, and wherein the same single heat exchanger
both: pre-cools and conducts the fluid to the wafer/hybrid chuck,
and receives back the fluid from the wafer/hybrid chuck to
contribute to the pre-cooling of the fluid.
2. The method according to claim 1, wherein the portion is firstly
heat-treated and then allowed to flow out within the space.
3. The method according to claim 1, wherein the portion is
heat-treated outside the space and then fed back to the space.
4. The method according to claim 1, wherein the portion is allowed
to flow out within the space directly after it leaves the
wafer/hybrid chuck.
5. A method for conditioning semiconductor wafers and/or hybrids,
comprising: preparing a space which is essentially enclosed by a
container and has a wafer/hybrid chuck which is located therein and
has the purpose of holding a semiconductor wafer and/or hybrid
applied to the wafer/hybrid chuck; pre-cooling a dry fluid in a
single heat exchanger outside the space; conducting the pre-cooled
fluid out of the single heat exchanger into the wafer/hybrid chuck
via a first line, and then through the wafer/hybrid chuck to cool
the wafer/hybrid chuck; wherein at least a portion of the fluid
having been conducted through the wafer/hybrid chuck is used to
condition the atmosphere within the space; wherein a first portion
of the fluid having been conducted through the wafer/hybrid chuck
is firstly conducted via a second line out of the wafer/hybrid
chuck back to the single heat exchanger, then heated by using a
residual coldness of the first portion to cool the single heat
exchanger to contribute to the pre-cooling of the fluid in the
single heat exchanger, and then conducted via a third line from the
single heat exchanger into the space, before being allowed to flow
out within the space, wherein a second portion having been
conducted through the wafer/hybrid chuck is allowed to flow out
within the space directly after it leaves the wafer/hybrid chuck,
and wherein the same single heat exchanger both: pre-cools and
conducts the fluid to the wafer/hybrid chuck, and receives back the
fluid from the wafer/hybrid chuck to contribute to the pre-cooling
of the fluid.
6. The method according to claim 5, wherein at least one of the
first and second portions can be regulated in terms of flow
rate.
7. The method according to claim 2, wherein the portion is
heat-treated in that it is used for precooling the fluid, outside
the space before said portion is allowed to flow out within the
space.
8. The method according to claim 1, wherein the pre-cooled fluid,
when conducted through the wafer/hybrid chuck in order to cool the
wafer/hybrid chuck, crosses the wafer/hybrid chuck in a cooling
coil or cooling pipe.
9. The method according to claim 5, wherein the pre-cooled fluid,
when conducted through the wafer/hybrid chuck in order to cool the
wafer/hybrid chuck, crosses the wafer/hybrid chuck in a cooling
coil or cooling pipe.
Description
The present invention relates to a method and a device for
conditioning semiconductor wafers and/or hybrids.
It is known to carry out test measurements on semiconductor wafers
typically in a temperature range between -200.degree. C. and
+400.degree. C. For the heat treatment a semiconductor wafer is
applied to a sample stage which is cooled and/or heated according
to the desired temperature. In the process it is necessary to
ensure that the temperature of the semiconductor wafer does not
drop below the dew point of the surrounding gaseous medium since
otherwise moisture condenses on the surface of the wafer or icing
occurs, which impedes or prevents the test measurements.
FIG. 5 shows a schematic cross-sectional view of a conditioning
device for the purpose of explaining the problems on which the
present invention is based.
In FIG. 4, reference symbol 1 designates a space in a container 5
in which a sample stage 10 which can be temperature controlled is
provided and on which a semiconductor wafer (not shown) can be
positioned for test purposes. The volume of the container 5 is
usually between 400 and 800 litres.
The space 1 is enclosed essentially by the walls of the container 5
which have bushings for electrical lines and media supply lines as
well as, if appropriate, bushings for probes which are to be
attached externally and with which the test measurements
semiconductor wafer shown are to be carried out. However, this
space 1 must not be hermetically sealed by the container 5
depending on the application but must at least be enclosed to such
an extent that undesired penetration of moist ambient air can be
prevented by building up an internal excess pressure.
The sample stage 10 (also referred to as chuck) has a thermal
insulation 15 via which it is connected to a usually movable base
20. A corresponding movement mechanism (not shown) is generally
adjustable in the X, Y and Z directions. If the movement mechanism
is not located in the container, a seal has to be provided between
the base and container.
Furthermore, a heating device 90, which can be supplied from the
outside with electrical current for heating purposes and which has
a temperature probe (not shown), is integrated into the sample
stage 10.
Reference symbol 100 designates a dew point sensor by means of
which the dew point within the container 5 can be determined and
which can supply a corresponding signal to a monitor 101 outside
the container 5. The dew point sensor 100 is used in particular for
the sake of reliability when opening the device so that, for
example, compensatory heating can be carried out in order to avoid
condensation of water.
Furthermore, outflow elements 30 (oBdA. only two are shown) via
which dried air from outside, or a similar fluid such as, for
example, nitrogen, can be introduced via a line r1 into the
container in order to drive out moist ambient air from the
container 5. This air is firstly fed externally to an air drier 3
via a line r00 and then fed into the line r1.
A separate unit, which is connected to the container 5 via a
corresponding electrical line 11 and a media supply line r2, is the
temperature control rack 2 which has the following devices.
Reference symbol 80 designates a temperature controller which can
regulate the temperature of the sample stage 10 by heating by means
of the heating device 90, the sample stage 10 simultaneously or
alternatively being rinsed with air for cooling purposes, as is
explained in more detail below.
Reference symbol 70 designates a temperature regulating device to
which dried air is fed via the lines r0 and i1 from, for example, a
gas bottle or from an air drier, and which has a heat exchanger 95
which is connected to cooling assemblies 71, 72 by means of which
it can be cooled to a predetermined temperature.
The dried air which is fed via the lines r0, i1 is conducted
through the heat exchanger 95 and then fed via the supply line r2
into the container 5 to the sample stage 10, through which it
crosses in corresponding cooling coils or cooling pipes (not
shown). The dried air which has cooled the sample stage 10 leaves
it via the line r3 and is conducted out of the container 5 to the
atmosphere.
The dried air, which is conducted into the container 5 via the
outflow elements 30 in order to condition the atmosphere of the
container 5 is usually kept at room temperature so that only the
surface of the sample stage 10 is kept at the desired measuring
temperature, for example -20.degree. C., but the other elements in
the container 5 are approximately at room temperature. This dried
air which is fed via the outflow elements 30 flows out of the
container 5 through slits or gaps (not shown) or a separate outlet
line.
The fact that a relatively high consumption of dried air occurs
because said air, on the one hand for conditioning the atmosphere
and on the other hand for cooling the sample stage 10, is blown
through the container 5 and into the atmosphere, proves
disadvantageous in this known device for conditioning semiconductor
wafers. As a result, the consumption of dried air is relatively
high. A failure of the air drier 3 also brings about immediate
icing of the test wafer at corresponding temperatures.
For this reason, the object of the present invention is to specify
a method and a device for conditioning semiconductor wafers and/or
hybrids, which permit more efficient conditioning.
The method according to the invention having the features of claim
1 and the corresponding device according to claim 9 have, in
comparison with the known solution approach, the advantage that the
dried gas, for example the dried air, can be used efficiently.
Further advantages are the high level of operational reliability
and the fact that freedom from ice and condensation is ensured
because the dry air leaving the wafer/hybrid holding device is
always below the dew point of the temperature at the wafer/hybrid
holding device.
The idea on which the present invention is based is that at least a
portion of the gas leaving the wafer/hybrid holding device is used
to condition the atmosphere within the space. In the present
invention, cooling air is therefore used simultaneously at least
partially as dry air. It is advantageous if the portion of gas is
firstly heat-treated and then allowed to flow out within the
space.
For example, the portion is heat-treated outside a container and
then fed back to the container. A particular advantage of this
example is that a higher level of cooling efficiency is made
possible by correspondingly feeding back the air from the sample
stage to outside the container. In other words, the fed-back,
cooled air can be additionally used either for precooling the
fed-in dried air or for cooling specific assemblies and not only
for cooling the wafer/hybrid holding device.
However, it is alternatively or additionally possible for a portion
of the gas to be allowed to flow out within the container directly
after it leaves the sample stage. Since it is not expedient to
allow it to flow out directly at all temperatures, a corresponding
regulating valve is to be provided for this portion of gas.
Advantageous developments and improvements of the respective
subject matter of the invention are given in the subclaims.
According to one preferred development, the line device has a first
line via which the fluid can be conducted from outside the space
into the wafer/hybrid holding device, a second line via which the
fluid can be conducted from the wafer/hybrid holding device to
outside the space, and a third line via which the fluid can be fed
back from outside the space into the space. A temperature
regulating device is provided between the second and third
lines.
According to a further preferred development, outflow elements are
provided at the end of the third line.
According to a further preferred development, the line device has a
first line via which the fluid can be conducted from outside the
space into the wafer/hybrid holding device, and a fourth line via
which the fluid can be conducted from the wafer/hybrid holding
device into the space.
According to a further preferred development, the line device has a
second line via which the fluid can be conducted from the
wafer/hybrid holding device to outside the space, and a third line
via which the fluid can be fed back into the space from outside the
space. A temperature regulating device is provided between the
second and third lines.
According to a further preferred development, a valve is provided
for regulating the flow rate of the fourth line.
According to a further preferred development, the temperature
regulating device has a heating device.
According to a further preferred development, the temperature
regulating device has a heat exchanger to which at least a portion
of the fluid leaving the space can be conducted.
According to a further preferred development, the heat exchanger is
used to precool the fed-in fluid.
According to a further preferred development, the line device is
designed in such a way that the portion leaving the heat exchanger
can be fed back at least partially into the space in order to
condition the atmosphere.
According to a further preferred development, a further line is
provided via which dry fluid can additionally be conducted directly
into the space from outside the space.
According to a further preferred development, the space is
essentially enclosed by a container.
Exemplary embodiments of the invention are illustrated in drawings
and will be explained in more detail in the following description.
In said drawings:
FIG. 1 is a schematic illustration of a first embodiment of the
conditioning device according to the invention;
FIG. 2 is a schematic illustration of a second embodiment of the
conditioning device according to the invention;
FIG. 3 is a schematic cross-sectional view of a third embodiment of
the conditioning device according to the invention;
FIG. 4 is a schematic cross-sectional view of a fourth embodiment
of the conditioning device according to the invention; and
FIG. 5 is a schematic cross-sectional view of a conditioning device
for the purpose of explaining the problems on which the present
invention is based.
In the figures, identical reference symbols designate identical or
functionally identical components.
FIG. 1 is a schematic illustration of a first embodiment of the
conditioning device according to the invention.
In what follows, components which have already been described above
in conjunction with FIG. 5 will not be described again in order to
avoid repetitions.
Reference symbol 80' designates a modified temperature controller
which can not only regulate the temperature of the sample stage 10
by means of the heating device 90 but is also coupled to the dew
point sensor 100 via a line 12 and can thus initiate automatic
compensatory heating when there is a risk of condensation of
water/icing.
In the first embodiment according to FIG. 1, a heating device 105
is additionally integrated into the temperature regulating device
70 and is not in direct contact with the heat exchanger 95. Instead
of ending at the ambient atmosphere, the line r3 is conducted to
the heating device 105 so that the dry air which has left the
sample stage 10 is, as it were, fed back to the temperature control
rack 2 and after it has passed through the heating device 105 it is
conducted back via the line r4 to the container 5 in which it flows
out into the space 1 through outflow elements 40 for conditioning
the atmosphere.
The reference symbol 4 designates a temperature sensor for sensing
the temperature in the space 1, which sensor supplies a
corresponding temperature signal TS to the temperature regulating
device 70 which is used to regulate the temperature by means of the
heating device 105.
By virtue of this arrangement, the dried air can fulfil a double
function, specifically firstly cool the sample stage 10 and then
condition the atmosphere of the space 1 before it is fed back to
the ambient atmosphere through openings in the container 5, and is
thus used more effectively.
FIG. 2 is a schematic illustration of a second embodiment of the
conditioning device according to the invention.
In the second embodiment according to FIG. 2, a line r5 branches
off from the line r2 directly before the sample stage 10 and is
also conducted through the sample stage 10 in the form of a cooling
coil or a cooling pipe, but then leaves the sample stage 10 at a
different point from that of the line r3 and from there via a
controllable outlet valve 45 which conducts corresponding dried air
directly into the container 5 after it leaves the sample stage
10.
Since this would lead to problems at very low temperatures in
certain applications, this option of conducting the dry gas via the
line r5 into the container 1 can be regulated by means of the
outlet valve 45. The regulation can be carried out in a customary
way, for example by remote control or in a wire-controlled
fashion.
Otherwise the second embodiment is of identical design to the first
embodiment described above.
FIG. 3 shows a schematic cross-sectional view of a third embodiment
of the conditioning device according to the invention.
Reference symbol 80' designates a further modified temperature
controller which also controls the temperature regulating device 70
via the control line ST and thus plays the role of a central
temperature control system.
In the third embodiment according to FIG. 3, a portion of the dry
air which is fed back via the line r3 is branched off before the
heating device 105 via line i3 and conducted through the heat
exchanger 95 where it contributes to the cooling in the same way as
the dry air which is freshly fed in via the lines r0, i1. The dry
air leaves the heat exchanger 95 via the line i4, and directly
after the heating device 105 it is combined with the air which has
flowed through the heating device 105. From the corresponding
junction point, this dried air is conducted, in precisely the same
way as in the first embodiment, via the line r4 and the outflow
elements 40 into the container 5 for conditioning its
atmosphere.
Furthermore, this embodiment provides a controllable mixing valve
46 and a bypass line r10 by means of which the heat exchanger 95
can be bypassed.
The particular advantage of this embodiment is that a "residual
coldness" of the dried air which flows back from the sample stage
10 can be used to cool the heat exchanger and at the same time can
be fed back into the container 5 after heating.
Otherwise, the second embodiment is constructed in the same way as
the first embodiment described above.
FIG. 4 is a schematic cross-sectional view of a fourth embodiment
of the conditioning device according to the invention.
Reference symbol 85 in FIG. 4 designates an additional
gas-temperature controller to which dry gas, for example dried air,
is fed via lines r0, i2 from the same gas source as that of the
heat exchanger 95, said air being placed at a predefined
temperature by said controller and then conducted into the interior
of the container 5 via the line r1 and via the outflow element
30.
The direct feeding in of dried air via the outflow element 30 in
the container 5 is therefore additionally provided in this
embodiment but it can also be configured in such a way that it can
be switched off if the throughflow rate through the sample stage 10
is completely sufficient for conditioning the atmosphere within the
container 5.
Although the present invention has been described above with
reference to preferred exemplary embodiments, it is not restricted
to them but rather can be modified in a variety of ways.
In particular it is to be noted that the exemplary embodiments
above can of course be combined with one another. Additional line
connections and regulating valves for the respective gas flow,
which can be controlled manually or electrically, can also be
provided.
In addition, the residual coldness of the fed-back gas can be used
not only for cooling the heat exchanger 95 but also for cooling any
desired other assemblies or heat exchangers before said residual
coldness is fed back to the container 5.
The invention is also not restricted to gaseous dried air but can
in principle be applied to any other fluids.
Furthermore, the wafer/hybrid holding device is not restricted to a
sample stage or chuck but rather can be varied as desired, for
example as a clamp device or the like.
* * * * *